After a damp and overcast morning session, teams competing in the 15th Annual Petit Le Mans powered by Mazda enjoyed their first official dry track time at Road Atlanta Thursday afternoon. Muscle Milk Pickett Racing set the pace in P1, while BMW Team RLL was the GT leader in the 60-minute session.

Klaus Graf set the fastest lap in Thursday's second practice session, a 1:11.209 (128.411mph), in preparation for Muscle Milk's quest for the P1 title. Graf, Lucas Luhr and Romain Domas must finish 70 percent of the 1,000-mile/10-hour race distance on Saturday to be named the 2012 P1 champions.

In GT, outgoing champions BMW Team RLL were the quickest. Jorg Müller entered a 1:20.137 (114.105mph) in the No. 55 BMW E92 M3. Müller is partnered with Bill Auberlen and Jonathan Summerton for Petit Le Mans.

OAK Racing, one of the seven European Le Mans Series teams entered in Petit Le Mans, was tops in P2. Driver Olivier Pla clocked a 1:13.758 (123.973mph) in the No. 35 Morgan Nissan. Pla, who drives with Jacques Nicolet and Bertrand Baguette, was followed by the quickest ALMS P2 squad, Level 5 Motorsports, by 0.138 seconds. Four-time IndyCar champion Dario Franchitti set the fastest lap in the team's No. 055 HPD ARX-03b, which he shares with his younger brother Marino and Scott Tucker.

Dempsey Racing's Ryan Lewis was the class of the PC field. Lewis turned a quick lap of 1:16.360 (119.749mph), nearly a second quicker than the next PC entrant, PR1 Mathiasen Motorsports. Lewis drives with Duncan Ende and Henri Richard.

Newly crowned GTC champions Alex Job Racing top that class' time sheets. Leh Keen turned a 1:25.020 (107.551mph) in the No. 22 Porsche 911 GT3 Cup he shares with Cooper MacNeil and Dion von Moltke.

The two GTE-Am entries, AF Corse and IMSA Performance Matmut were separated by just 0.337 seconds. AF Corse led the way with Marco Cioci in the No. 60 Ferrari F458 Italia, which he shares with Piergiuseppe Perazzini and Matt Griffin. Cioci set a 1:22.385 (110.991mph).

The Nissan DeltaWing, which was damaged in a crash during Wednesday's test session, was expected to return to the track for night practice.